Connection devices of this type are already known, in particular from the French patent 86 15553, published under the number 2 606 558, in which devices the catch is provided with an internal reception window defined by a continuous edge which is closed on itself, to receive the wires after they have been introduced substantially parallel to themselves.
There are circumstance in which the cables have to be introduced substantially transversely to themselves and, moveover, parallel to the relative movement of the clip and of the catch, such as that for which the device of the U.S. Pat. No. 3,945,705 was designed, i.e. for automatic introduction of the cables by placing by machine.